OK, a word in my defense! Not all cyclists behave like this, I don't!
If you are in a rush, the roads are much quicker than the towpath, although admittedly I'm not there at rush hour times.
Also, there are already many chicanes on this towpath, from Camden all the way to Hackney. Few more won't hurt, but there are also speed humps most of the way along by bridges too. These things probably make the inconsiderate ones go faster between the obstacles to make up the time!
Ringing of bells is asked for, and at a blind spot like a bridge hole, it's the right thing to do. It's also the right thing to do to stop and make way. I do, and so do many other cyclists I've seen!
We're not all bad, like not all dog owners leave dog mess. Please don't over generalise.......